Abstract: As an advanced composite molding technology, automatic placement technology is widely used to process complex composite components. In this study, the number of compacted fibers, angular deviation and radius of curvature are taken as evaluation indexes. Through the comparison of different trajectory planning algorithms, the trajectory planning algorithm suitable for marine closed surface is selected. Based on the overlap factor, the trajectory coverage is analyzed, and a prepreg yarn increase and decrease algorithm suitable for complex surface is proposed to achieve the uniform distribution of overlap and gap. A zonal trajectory optimization method is proposed based on the marine closed curved structure to reduce the number of fiber breaks. Finally, simulation and experimental analysis are carried out to verify the correctness of the algorithm.